By Josh Cosford, Contributing Editor
In fluid power, safety is always a concern. Everyone understands the force capacity of hydraulic actuators (which explains why some YouTube hydraulic press channels have millions of subscribers). Indeed, a high-powered hydraulic press can make nearly any material appear no stronger than modelling clay. It’s wise to respect the power of hydraulics, so most machine operators know to stay out of the way for their safety. Some tricks to improve hydraulic machine safety are less common than counterbalance valves and rod locks.
Ball valves are on the same level as poppet valves in their ability to prevent the passage of hydraulic fluid. Their ball and socket design leaves little room for fluid passage, which makes them a great safety item. Any time you wish to absolutely block flow, the ball valve provides a solid option.
For example, there may be circumstances when you want your hydraulic power unit active while preventing downstream functions from operating, such as when making adjustments on a pump’s pressure compensator while other parts of the machine remain safely inert. An electrical panel lockout prevents all hydraulic functions from operating. By adding a locking ball valve to the pressure line of the variable displacement piston pump, the maintenance team can lock out the pump only while allowing it to run on standby. Anyone working on the downstream portion of the machine will be safe.
Ball valves are underutilized for their capacity to prevent leaks and, therefore, oil spills. That same ball valve mounted directly to the port of your hydraulic motor may be closed during pump replacement to prevent the pump pressure line from draining. This tactic saves precious hydraulic fluid and prevents it from making a dangerous slip hazard all over the floor.
Did you know ball valves may be optioned with not only locks but also limit switches to monitor the valve position? Limit switches send their signal to the PLC to offer safety control logic. In most cases, a signal (or lack thereof) will prevent the machine from starting. When servicing a hydraulic power unit with flooded suction, the locking monitored ball valve offers a few safety benefits. The ball valve allows the technician to close the suction port to avoid draining the reservoir before servicing the pump.
The lock applied by the technician prevents anyone from accidentally closing or opening the ball valve with the pump disconnected. Draining forty gallons of fluid all over the floor also drains the wallet, never mind the massive slip hazard with a twenty-foot radius. Additionally, the limit switch attached to such a ball valve lets the PLC know the valve may still be locked open even after the pump is reinstalled. Finally, starting a pump with a blocked suction line is another method to quickly burn through your financial resources.